#include <iostream>
using namespace std;
int main()
{
int ans=10,time=10;
bool flag=0;
do
{
flag=0;
if(time<=18&&time%2==0)flag=1;
if(time<=36&&time%4==0)flag=1;
if(flag)ans++;
time++;	
}while(time<=36);
cout <<ans<<endl;
return 0;	
}
